1. Field of Invention
The invention concerns a process and a device for supplying printing ink to and educing printing ink from a squeegee device of an inking system on a rotary printing press and for cleaning the squeegee device, which comprises a squeegee blade carrier, provided with a longitudinally running trough, with squeegee blades that are adjustable on a form inking roller that, together with the form inking roller and the trough, delimit an ink chamber, and comprise lines and pumping devices powered by motors for supplying and educing the ink or the cleaning agent into and out of the ink chamber.
2. Description of the Prior Art
A device of this type is known from the German patent DE 195 48 535 C2 with which residual ink can be removed not only from the ink chamber of the squeegee device, but also from the supply and evacuation lines while reducing the amount of dissolving agent used for cleaning, in that the ink from the ink chamber is pumped back into an ink tank via the evacuating lines, in that the dissolving agent is subsequently pumped out of a dissolving agent tank via the supply lines into the ink chamber and is channeled via the evacuating lines into the ink tank for a predetermined amount of time, in that admission into the ink tank is subsequently stopped and in that the dissolving agent still soiled by the ink is pumped into a waste tank for a predetermined amount of time, in that the supply flow of dissolving agent from the dissolving agent tank is subsequently interrupted and in that the dissolving agent still present in the circulation system is pumped into the waste tank as well, in that fresh dissolving agent is subsequently pumped via the supply lines and educing lines in a closed cleaning circuit for a predetermined amount of time and in that finally, the dissolving agent that was fed through the closed cleaning circuit is channeled into the waste tank. The known device is elaborate to the extent that an ink pump, a dissolving agent pump and two mutually connected pumps are provided for pumping ink and dissolving agent back into the ink tank or into the waste tank. The use of several pumps creates high procurement costs on the one hand.
On the other hand, it must be taken under consideration in the case of the known device that during the circulation of the ink under printing operations, a larger volume must be fed back into the ink tank than is being pumped into it, since the ink in the ink chamber becomes enriched with air. As a consequence of this, the evacuating (i.e., return) pump must pump a larger volume than the delivery (i.e., feed) pump. This volumetric pumping ratio must be permanently monitored and readjusted manually when required.